1. Field of the Invention
The present invention relates to the handling of partially completed books during a book manufacturing process and particularly to creation of stable stacks of book blocks, subsequent to the stitching thereof, which may be placed in palletized storage for future use. More specifically, this invention is directed to a delivery system for receiving book blocks from a book-sewing machine, and especially to apparatus for acquiring stitched book blocks which exit a sewing machine in a first orientation and automatically manipulating the thus acquired book blocks so as to create stable book block stacks which may be stored for future processing. Accordingly, the general objects of the present invention are to provide novel and improved methods and apparatus of such character.
2. Description of the Prior Art
Delivery systems which are located intermediate book-sewing machines and a palletizing station are known in the art. Such known systems include a transverse stack conveyor, which is located at the discharge end of the sewing machine, and an associated stacking table on which the sewed book blocks accumulate. The book blocks which exit a book-sewing machine will be vertically oriented, i.e., will be supported on their front edges. The prior art delivery systems have customarily conveyed the stitched book blocks in the vertical orientation and guided at their opposite ends. The basting threads which extend between the individual book blocks are automatically cut, by means of a cutting device, to separate the individual book blocks as they are carried along the delivery system.
The separated book blocks must be removed from the delivery system and stacked on pallets. This palletizing is a very labor intensive operation. In the interest of reducing the labor required to manufacture a book, attachments which rearrange the book blocks to place them in a separated horizontal orientation have been devised for use with book sewing machines. For example, it has been proposed to provide a first conveyor, located behind the transverse stack conveyor, onto which the book blocks are individually pushed. The attachment also includes a second conveyor, oriented at right angles to the transverse stack conveyor, onto which the book blocks are dropped to form a partial stack. As an alternative to the use of such a second conveyor, a stacking mechanism may be employed. The book blocks to be stacked free fall onto the stacking mechanism which will rotate through an angle of 180.degree. after each stack has been formed.
In order to ensure stable storage, it is important that precise alignment of the individual book block layers be maintained. That is, the book block stacks must be formed in such a manner that the possibility of relative sliding motion between the layers comprising a stack of book blocks on a pallet is minimized.
In the case of book-sewing machines which do not have the above-briefly discussed stack forming attachments, the removal of the book blocks from the transverse stack conveyor for subsequent stacking on a pallet is carried out by hand. During this hand stacking, in order to form stable stacks, the book blocks must be individually arranged so that the front edge of each book block, or the front edges of the book blocks of a partial stack, will be located in alignment with the sewed, spine edge of the adjacent book blocks or partial stacks. Restated, in each stack, the adjacent book blocks or partial stacks of book blocks are rotated by 180.degree. relative to one another. The removal of book blocks from the transverse stack conveyor and the stacking thereof on pallets while retaining the precise alignment in which the printed sheets were conveyed, and while also ensuring that the above-described front-to-back orientation is achieved, is a task requiring great effort and a high degree of manual dexterity, particularly in the case of high performance book-sewing machines.
In actual practice, both in the manual stacking of book blocks or partial book blocks removed from a transverse stack conveyor and in the use of the above-briefly described attachments which also require manual placement of the book blocks on pallets, the alignment of the book block stacks is often lost due to shifting of the individual book block layers in relation to one another. When the palletizing operation has been completed, any such misalignment is extremely difficult or impossible to correct. The misalignment results in unstable storage and can cause degradation of the book blocks which makes further use thereof in the completion of the book manufacturing process difficult.